Radar for Smart Cities: Principles and Applications

Radar is an acronym for RAdio Detection And Ranging. It uses radio waves to detect objects, relative position, size, range, and velocity. For many of us what comes to mind are the long-range radar antenna you might encounter at the airports or military installations. This article is focused on a smaller form factor and its potential in smart city applications.

A radar simply uses high frequency electromagnetic waves by transmitting radio frequency energy to an object and analyses the reflection that comes back.

We first looked into radar to detect traffic. Our first smart streetlights installation was a Proof of Concept in UiTM led by the facility energy manager En Razali Abd Hadi. His main goal is to reduce the energy consumption of the streetlights. Universities always need the lights to be on for students’ safety, but the amount of lights needed with no traffic can be a lot lower than when you’re trying to navigate the road at night.  As universities have lower traffic patterns at night and during semester breaks, there’s a sizeable amount of energy that can be saved by dimming the lights when no traffic is present.

We favoured radar as its detecting range is much further than ultrasonic sensors. We needed to detect incoming vehicles so that we can increase the lux output of the lights before the vehicle reaches the intended stretch of streetlights.  More importantly we needed to know the relative size of the object, is it a person, a cat or a car?

Camera is another good option, but cameras come with some long-term maintenance requirement. Cameras have higher purchase price and operational cost to send data. It is a complex device with sensitive electronics which reduces its reliability. To detect traffic, we would also need to have a GPU or edge inferencing which would drive up the cost of the cameras.  Cameras are not reliable in bad weather (when we need it the most). Radar systems have lower parts count and lower complexity which contributes to its lower cost and better reliability.

The list here are not exhaustive list of potential smart city applications:

• Precision control of streetlights
  • Detection of traffic for traffic lights
  • Radar speed sign
  • Water tank level detection
  • Flood detection

We demonstrated the traffic detection for traffic lights using radar during the Maxis Nb-IoT Challenge.  The traffic lights we see today uses magnetic loop sensors. Loop sensors have limited lifetime and are expensive to replace (requires digging the road.) It is also not sensitive enough to detect small motorcycles, which represents a large portion of traffic users in Asian cities.

We are working with the JKR IoT Taskforce on the radar for traffic lights. We are also working with team on the radar speed sign because speed is a major contributing factor in traffic accidents. Research shows that about 80% of speeders will slow down when notified they are speeding. We hope to have one installed on the street in Q2 2020.

“IoT Radar allows us to effectively manage our traffic lights allowing for more efficient traffic flow”: Dr Megat Zuhairy. Chairman JKR IoT taskforce.

Radar is robust, accurate and can be used in many applications in place of cameras. The adoption of radar in the automotive sector is helping to drive down cost of devices and opening up many use cases that might not have been viable in the past.